I will chime in.
This is the parable of the sower and verses 20-21 IMO is a prime example of those who stumble or in some translations, "fall away"
20 But he who received the seed on stony places, this is he who hears the word and immediately receives it with joy;
First let's consider this verse. Jesus is explaining the parable and he goes on to say that their will be those who will hear the word and immediately receive it with joy. We have to ask ourselves first, what meaning can we subscribe to the word "Receives". Greek states this...
1. to take
a. to take with the hand, lay hold of, any person or thing in order to use it
1. to take up a thing to be carried
2. to take upon one's self
b. to take in order to carry away
1. without the notion of violence, i,e to remove, take away
c. to take what is one's own, to take to one's self, to make one's own
1. to claim, procure, for one's self 1c
d. to associate with one's self as companion, attendant
1. of that which when taken is not let go, to seize, to lay hold of apprehend
2. to take by craft (our catch, used of hunters, fisherman, etc.), to circumvent one by fraud
3. to take to one's self, lay hold upon, take possession of, i.e. to appropriate to one's self
4. catch at, reach after, strive to obtain
5. to take a thing due, to collect, gather (tribute)
e. to take
1. to admit, receive
2. to receive what is offered
3. not to refuse or reject
4. to receive a person, give him access to one's self, 1d
2. to regard any one's power, rank, external circumstances, and on that account to do some injustice or neglect something
1. to take, to choose, select
2. to take beginning, to prove anything, to make a trial of, to experience
3. to receive (what is given), to gain, get, obtain, to get back
From this definition we should clearly see that he that "receives" the word receives it as something that he comprehends, takes hold of as to use it, making it his own, won't let go, not to refuse or reject. Christ then states he receives it with JOY. This person get's excited about the word.
So let's ask ourselves. Is this person at this time, "saved"? Has he received grace?
Absolutely. He hears the "word", and then immediately receives it with joy. So not only does he understand, grasps, and accepts this word he hears, he also is excited about this word he just receieved. Let me give you an example. Let's say that I tell my daughter that we are going to disney world. I have just given her a word. She hears what I say and get's excited over it. Why? Because she believes her daddy won't lie to hear and so she is overwhelmed with joy and anticipation. If she didn't believe me, would she get excited, or happy with joy? I doubt it.
21 yet he has no root in himself, but endures only for a while. For when tribulation or persecution arises because of the word, immediately he stumbles.
Here's the unfortunate part of the parable. Christ says that this man has no root in himself. Basically meaning that that he is not grounded. Picture this man standing tall like a huge tree, with no roots. Now here is the most important part of this section of scripture. Chrst says that "For when tribulation or persecution arises because of the word" he does what, STUMBLES, and in some interpretations it says "falls away" because of the WORD that he received.
Basically we have someone here who hears the word, accepts this word, is all excited because of this word, goes out into the world, then get's persecuted for what he has received and believed, can't handle the persecution because he doesn't know how to defend and rightly divide the word. So he falls away and stumbles off the path that he once received with joy.
